Layers of minerals revealed by erosion give Vinicunca its distinct colorations

Inca trail interactive map

Machu Picchu gets all the attention, but it’s definitely not the only Inca ruin in the area. Some dedicated trekkers opt to see the sites through a multi-day hike down the Inca Trail, which spans 26 miles from the Sacred Valley to Machu Picchu and reaches elevations as high as 13,800 feet above sea level. This 3D tour gives a sneak-preview of the ruins along the route, and the intense topography.

What is the rarest color in nature?

Plants, animals, or minerals found in nature bear almost every color imaginable. There are two factors that influence what hues you see in the wild: physics and evolution. So, which colors are you least likely to see in the natural world? Victoria Hwang explores one of nature’s rarest spectacles.

Cerulean eruptions result from sulfur being heated by molten rock

During eruptions, warm-colored lava at temperatures between 700 and 1,200 degrees Celsius (1,300 and 2,200 degrees Fahrenheit) burns minerals as they escape from underground reservoirs. In some volcanoes, such as Indonesia's Kawah Ijen and Ethiopia's Danakil Depression, abundant sulfur compounds that burn with blue flames appear to change the color of the melted rock.

The conditions needed for cloud iridescence, or rainbow clouds

The relatively rare phenomenon occurs when sunlight scatters off tiny water droplets or ice crystals in thin, newly-forming or semi-transparent clouds, such as altocumulus, cirrocumulus, lenticular, and cirrus varieties. This effect is similar to what is seen in soap bubbles and mother-of-pearl shells and produces pastel-like colors.

The last Inca grass suspension bridge in Peru

High in the Peruvian Andes, the aging Q’eswachaka bridge sags precariously over the Apurímac River. It has been built and rebuilt continuously for five centuries. Read more about it here.

Niagara Falls flows over 400-million-year-old layered rock

The falls cut through distinct layers of ancient rock: a hard cap of Lockport Dolomite sits atop softer layers of Rochester and Queenston Shale. This structure allows the falls to maintain a steep vertical drop as erosion undercuts the caprock.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

The mysterious qualities of obsidian and magnetite

Obsidian is a dark volcanic glass created when lava cools quickly and frequently contains magnetite, a key early mineral used in compasses. Large deposits were discovered and used in central Mexico by the Toltecs roughly 1,000 years ago at the ancient site of Teotihuacan. This essay explores obsidian's cultural impact and the mysterious presence of magnetite in migratory birds.

The Valley of Mexico sits over 7,000 feet above sea level

Once dominated by the shallow waters of Lake Texcoco, the high-altitude Valley of Mexico—surrounded by volcanic peaks—was home to the Aztec capital Tenochtitlan. This resource breaks down the region’s unique geography and why it became a cradle of Mesoamerican civilization.

The centuries-old history of titanium white goes back to the Inca

Titanium white can be found in items ranging from paint to pills. Though it was created in New York in 1908, the pigment was first used hundreds of years earlier by the Inca, according to this article.

View a gallery of diagrams for each volcano type with glossaries

The three major types of volcanoes—cinder cone, composite, and shield—each exhibit unique, lesser-known subterranean and surface features, including lava bombs, lahars, and spatter. Other types of volcanoes include lava domes, calderas, fissure volcanoes, and Maars and tuff rings.

Ceren: The Maya Pompeii (sans all the bodies)

The Maya village of Ceren in El Salvador was preserved by volcanic ash from 1,400 years ago, revealing insights into ancient Maya commoners' lives. Ceren villagers had autonomy in their daily activities, and excavations reveal evidence of communal decision-making and event hints at the presence of a community sauna. Dive into more of the archaeological finds on how businesses were run, how they prepared for disaster, and more.

Speleothems are diverse mineral formations that form in air-filled caves

Speleothems like stalactites and stalagmites form when water deposits minerals after a cave rises above the water table and fills with air. These formations preserve the mineral deposits, which may serve as climate proxies, for as long as a million years.

From the surface, Mars can appear butterscotch, golden brown, and even green

Images from orbiters, landers, and rovers show that Mars has a mix of surface colors resulting from variations in the mineral compositions of different regions. The reddish tint when viewed from Earth comes from kicked up particles of rusted iron.

Minerals, crystals, rocks, and gems explained

Have you ever wondered what differentiates a mineral from a rock or a crystal from a gem? This three-minute video from the American Museum of Natural History elaborates on the unique properties and compositions that separate minerals, rocks,...

Ancient sunken plates may influence mantle convection and surface motion

Research suggests sunken tectonic plates can collide, assemble, and break apart to form structures called large low-velocity provinces. LLVPs can significantly enrich rising magma plumes with elements commonly seen on Earth’s surface.

Critical mineral production may lift impoverished regions out of poverty

Mineral wealth can provide public revenue and economic livelihoods to those in mining regions. However, poor management and lack of oversight can cause human rights abuses, environmental degradation, and significant greenhouse gas emissions.

A 37.41 carat, bicolor diamond likely formed from two distinct geological processes

Discovered in a Botswana mine, half the stone is clear, having formed from carbon being squeezed under extreme heat and pressure into a tight crystal structure. The pink half formed earlier and resulted from minor bending of the crystal during tectonic activity without causing it to brown or break.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

Fly through the Valles Marineris, the largest canyon in the solar system

Stretching farther than the width of the continental US and with depths as much as four times those of the Grand Canyon, the Valles Marineris is believed to have formed when Mars’s crust tore open during intense volcanism in the planet’s past.

Explore Amazon rainforest species in this interactive

Explore plant and animal species from different parts of the rainforest, including the canopy, forest floor, and river basin while learning some general facts specific to the Amazon rainforest.

Venezuela's Lake Maracaibo is considered the lightning capital of the world

Spread across 140 to 160 nights, and as many as 10 hours per night, the region where the Catatumbo River flows into the semi-enclosed bay experiences approximately 1.6 million lightning strikes annually. The frequency of strikes may originate from warm Caribbean air interacting with cooler air from the Andes.

Bolivia's Salar de Uyuni is the world's largest salt flat

Often considered the largest natural mirror on Earth, the flat bed exhibits reflective properties, particularly after significant rainfall. However, its reflectivity varies spatially and temporally as water evaporates.

Rainfall and lush vegetation make the Great Smoky Mountains smoky

The national park is a rainforest that receives significant rainfall. When the vegetation on the mountains gets wet, it releases a gas that is smoky, and sometimes even appears blue, a phenomenon that gave the mountains (and the park) its name.

The extremophilic origins of watermelon snow and its impact on glacial melting

Also known as "blood snow," the red coloration is produced by snow algae that thrive in extremely cold conditions and take the shape of red spherical cysts in winter. To protect themselves from more intense summer solar radiation, these psychrophiles accumulate red, orange, and yellow pigments, intensifying their coloration and causing glaciers to reflect less sunlight than if they were white.

Color originates from the brain processing light of varying wavelengths

Various geometric models, including Newton's color circle of hue and saturation and the horseshoe-shaped XYZ space for mixing colors via vector mathematics, have been proposed to describe colors accurately. However, these models do not encapsulate the variety of psychological effects that cause perceived colors to differ from mathematical representations.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

Dirty lightning is a thunderstorm created from friction between rising and falling flows of ash and smoke during volcanic eruptions.

See a lunar eclipse share the night sky with the Milky Way

Photos taken at the Cerro Tololo Inter-American Observatory in Chile in March 2025 captured a blood moon and the Milky Way galaxy within the same field of view. The moon appears red from the bluer parts of its reflected sunlight being scattered by Earth's atmosphere.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

Explore the archaeological treasures of Pompeii, the city buried under volcanic ash when Mount Vesuvius erupted in 79 CE.

See photos of Meteora, a mountainous site in central Greece, home to 14th-century monasteries perched atop soaring outcroppings.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

Power lines are dotted with large, brightly colored balls to improve the visibility of these thin wires to helicopters and small planes and help prevent potential crashes.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

This poison ivy knowledge quiz—accompanied by photos of the plant's varied forms—may help you identify this common rash-inducing growth.

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

Waves off the coast of Nazaré, Portugal, can reach over 100 feet and are caused by the area's deep underwater canyon geography

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

'Grand Canyon of the Yellowstone,' a work by American painter Thomas Moran, inspired Congress to establish Yellowstone National Park.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Watch this video that uses Lego bricks to explain how venture capital works.

Ebola species have historically been named after where they were discovered, stigmatizing residents who live there, including Bundibugyo, in Uganda.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

In 2026, Finland was named the world's happiest country for the ninth consecutive year based on its wealth, social safety network, and high life expectancy, among other factors.

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.